Grinding machine



Aug. 4, 1959 Filed Feb. 18, 1957 O. E. HILL GRINDING MACHINE 3 Sheets-Sheet l INVENTOR 0/ VA E HILL Mum ATTORNEY Aug. 4, 1959 o. E. HILL 2,397,639

GRINDING MACHINE Filed Feb. 18. 1957 3 Sheets-Sheet 2 INVENTOR ONA E. HILL MU.W

ATTORNEY.

Aug. 4, 1959 o. E. HILL 2,897,639

GRINDING MACHINE Filed Feb. 18, 1957 3 Sheets-Sheet 5 l s w1 l a4 1; lZZ

INVENTOR O/vA HILL A TTOENEY ING MACIE "Diva R. Hill, West Boylston, Mass, assignor to Norton Company, Worcester, Mass, a corporation of Massachusetts This invention relates to grinding machines and more particularly to a work size control and compensating mechanism therefor.

One object of the invention is to provide a simple and thoroughly practical compensating mechanism for controlling the stopping of the end feeding movement of the grinding wheel. Another object is to provide a feed wheel with a pair of compensators, one for adjusting for oversize work and the other for undersize work. Another object is to provide a manually operable mechanism for precisely adjusting the stop abutment on the feed wheel to compensate for oversize or undersize work .pieces. Another object of the invention is to provide a fluid operated mechanism for actuating the oversize and un-dersize compensator-s.

A further object of the invention is to provide a manually operable gauge controlled mechanism for actuating the oversize and undersize feed compensators after a predetermined number of consecutive work pieces have been groiuid either oversize or undersize. Other objects will be in part obvious or in part pointed out hereinafter.

In the accompanying drawings, in which is shown one of various possible embodiments of the mechanical features of this invention:

Fig. 1 is a fragmentary cross sectional view through a grinding machine wheel feeding mechanism;

Fig. 2 is a fragmentary front elevation, on an enlarged scale, of the wheel feeding apron; and

Fig. 3 is a combined hydraulic and electric diagram of the actuating mechanisms and the controls therefor.

A grinding machine has been illustrated in the drawings comprising a base in which supports a transversely movable wheel slide 11 on a pair of spaced parallel antifriction slideways 12 (only one of which is shown in Fig. 1). The wheel slide 11 supports a rotatable wheel spindle 13 having a grinding wheel 14 mounted at one end thereof for grinding a cylindrical work piece 15, either by the conventional cylindrical-type or the centerless grinding method.

A driving mechanism is provided for the wheel spindle 13 comprising an electric motor 16 mounted on the upper surface of-the wheel slide 11. The motor 16 is provided with a motor shaft 17 having a multiple V- groove pulley 18 which is connected by multiple V- belts 19 with a multiple V-groove pulley 2i) mounted on the wheel spindle 13.

A feeding mechanism is provided for imparting a transverse feeding movement to the wheel slide 11. This mechanism comprises a rotatable feed screw 21 having a reduced cylindrical portion 22 at its left hand end. The cylindrical portion 22 is slidably keyed within. a rotatable sleeve 23 which is journalled in an anti-friction bearing 24 supported by the base it). The right hand end of the feed screw 21 is supported by anti-friction bearings 25 which are supported within a slidably mounted sleeve 26 which is slidably keyed within a cylindrical aperture 27 formed in the base 10. The wheel Patented Aug. 4, 1959 slide 11 is provided with a depending feed nut 28 which meshes with or engages the feed screw 21.

A hydraulically operated mechanism is provided for imparting a rapid positioning movement of the wheel slide 11 to and from .an operative position relative to the workpiece to be ground. This mechanism comprises a cylinder 30 which is fixedly mounted on the base 10 of the machine and is arranged in axial alignment with the axis of the feed screw 21 and the sleeve 26. The cylinder 30 contains a slidably mounted piston 31 which is connected to the right hand end of a piston rod 32. The left hand end of the piston rod 32 is fixedly connected to the sleeve 26.

A feeding mechanism is provided comprising a manually operable feed wheel 35 which is rotatably supported on a shaft 36. The feed wheel 35 is connected by a micrometer adjusting and compensating mechanism 37, to be more fully described hereinafter with a pinion 33 which meshes with a gear 39. The gear 39 is rotatably supported on the shaft 36. A gear 40 is formed integral with the gear 39 and meshes with a gear 4-1 which is mounted on the left hand end of a rotatable shaft 42. The left hand end of the shaft 42 is journalled in antifniction bearing 43. The right hand end of the shaft 42 is slidably keyed within the rotatable sleeve 23. be readily apparent from the foregoing disclosure that a rotary motion of the feed wheel .35 will be imparted through the gear mechanism above described to impart a rotary feeding motion to the feed screw 21 to impart a transverse feeding movement to the wheel slide 11 and the grinding wheel 14.

A hydraulically operated mechanism is provided for imparting a rotary motion to the feed screw 21 to produce the desired grinding feed. This mechanism comprises a cylinder 45 which contains a slid-ably mounted piston 45. The piston 46 is provided with rack teeth 47 on its upper surface which mesh with a gear 48. The gear 48 is journalled in spaced anti-friction bearings 49 and 50 (Fig. 1). A shaft 51 is rotatably supported within a central aperture formed within the gear 48. A gear 52 is fixedly mounted on the right hand end of the shaft 51. The gear 52 meshes with a gear 56 which is mounted on the shaft 42.

A manually operable clutch mechanism is provided to connect a gear 48 with the shaft 51 and the gear 52. This mechanismcomprises an internal gear 53 which is fixedly mounted on the gear 52 which may be thrown into mesh with an external gear 54 which is fixedly mounted relative to the gear 48. The left hand end of the shaft 51 is provided with an actuating knob 55 by means of which the shaft 51 may be moved in an axial direction to move the gear 52 together with the internal gear 53 toward the right (Fig. 1) out of mesh with the external gear 54- when it is desired to disconnect the piston 46 to render the fluid pressure operated mechanism inoperative.

A feed control valve (not shown) may be provided to control the admission to and exhaust of fluid from the rapid positioning cylinder 39 and the feed cylinder 45. This mechanism may be identical with that shown in the prior Uni-ted .States Patent No. 2,572,529 to H. A. Silve-n, dated October 23, 1951, to which reference may be had for details of disclosure not contained herein.

The pinion 38 is arranged so that it may be moved axially out of mesh with the gear s9 to facilitate adjusting the position of the feed wheel 35 relative to the gear 39 in setting up the feeding mechanism. A knob 68 is provided for moving the pinion 38 axially against the compression of a spring 69. The knob 63 is fixedly mounted on the left hand end of a spindle 70 which is in turn fixedly mounted or formed integrally with the pinion 38.

An automatically actuated mechanism is provided for imparting an incremental rotary motion to the pinionfifi,

It will in either a clockwise or counter-clockwise direction, to facilitate varying the position of a stop abutment 60 so as to compensate for oversize or undersize work. The stop abutment 60 is arranged so that when the feed wheel 35 is rotated in a counter-clockwise direction, it will engage a stop surface 61 formed on the upper end of a feed pawl 62 to limit the end feeding movement of the grinding wheel 14. A pivot stud 63 mounted on the front of the machine is provided to form a pivotal support for the feed pawl 62. A worm gear 71 is keyed to the spindle 70 and meshes with a worm 72 which is carried by a rotatable shaft or spindle 73. Due to the worm and worm gear reduction between the ratchet wheels "I i-84 and the pinion 38, an extremely fine compensating adjustment to the stop abutment 60 is obtained. For each tooth of the ratchet wheels 7484 picked at each actuation of the pawls 7888, the stop abutment 60 is adjusted by an increment of two one hundred thousandths of an inch (.00002).

A pair of fluid pressure actuated pawl and ratchet compensating mechanisms are provided for imparting a rotary motion to the spindle 73 in either direction. The pawl and ratchet compensators are substantially identical with the compensators disclosed in my copending patent application Serial No. 578,412, filed April 16, 1956, now US. Patent No. 2,834,159, dated May 13, 1958. The spindle 73' is provided with a ratchet wheel 74. A cylinder 75 (Fig. 3) mounted on the feed wheel 35 contains a slidably mounted piston 76 which is normally held in a downward position by a compression spring 77. The piston 76 is provided with a spring pressed pawl 78 which is arranged to move idly over the teeth of the ratchet wheel when fluid under pressure is passed through a pipe 79 into a cylinder chamber 80 to cause an upward movement of the piston 76. The upward movement of the piston is limited by an adjustable stop screw 81. When fluid under pressure is exhausted from the cylinder chamber 88 in v a manner to be hereinafter described, the released compression of the spring 77 causes a downward movement of the piston 76 during which movement the pawl 78 imparts a rotary motion to the ratchet. wheel 74 thereby imparting a rotary motion to the worm 72, to the worm gear 71 and to the pinion 38 to impart a clockwise rotary adjustment to the stop abutment 60 when the work pieces, being ground, are oversized.

Similarly the spindle 73 supports a ratchet wheel 84. A cylinder 85 is also carried by the feed wheel 35. The cylinder contains a slidably mounted piston 86 which is normally held in a downward position by a compression spring 87. The piston 86 is provided with a spring pressed pawl 88 which is arranged to actuate the ratchet wheel 84 during an upward movement of the piston 86. When fluid under pressure is passed through a pipe 89 into a cylinder chamber 90, the piston 86 together with the pawl 88 are moved upwardly against the compression of the spring 87. The upward movement of the piston 86 is limited by an adjustable stop screw 91. During the upward movement of the piston 86, the pawl 88 engages the teeth of the ratchet wheel 84 and imparts a counterclockwise rotary motion to the ratchet wheel 84 which in turn imparts a rotary motion to the worm gear 71 and the pinion 38 to move the feed wheel 35 together with the stop abutment 60 in a counter-clockwise direction so as to compensate for undersize work pieces. When fluid in cylinder chamber 90 is open to exhaust, the re leased compression of the spring 87 causes a downward movement of the piston 86. During the downward movement of the piston, the pawl 88 rides idly over the teeth of the ratchet wheel 84. It will be readily apparent from the foregoing disclosure that by adjustment of the stop screws 81 and 91, the stroke of the pawls 78 and 88 re-.

admission to and exhaust of fluid from the feed compensation cylinders 75 and 85. The control valve 95. is

a piston type valve having a slidably mounted valve member 96 which is normally held in a central position by a pair of balanced springs. The valve member 96 is provided with a plurality of integral spaced valve pistons forming spaced valve chambers 97, 98, 99, 100', 101, and 182. The valve member 96 is also provided with a central passage 103 which interconnects the valve chamber 98, 99, and 101.

A fluid pressure system is provided for supplying fluid under pressure to the various actuating mechanisms of the machine comprising a motor driven fluid pump 105 which draws fluid through a pipe 106 from a reservoir 107 and passes fluid under pressure through a pipe 108. A relief valve 109 is connected to the pipe 108 to facilitate by-passing excess fluid under pressure directly to the reservoir 107 to facilitate maintaining a substantially uniform operating pressure within the system. The pressure pipe 108 is arranged to convey fluid under pressure to the valve chamber 100.

The control valve 95 is arranged to not only supply fluid under pressure to the cylinders 75 and but also pensation, the feed screw 21 is actuated to impart a minute feeding movement to the grinding wheel slide 11. A simultaneous unwind and a wind movement is imparted to the feed screw 21 to facilitate taking-up the feed increment and also to take-up any backlash in the feed mechanism so as to precisely position the grinding wheel 14. As illustrated in Fig. 3 a pipe 111 is connected between the valve and a valve 112 and a pipe 113 with a cylinder chamber 114 formed on the right hand end of the cylinder 45. Similarly a pipe 115 is connected between the valve 95 through a valve 116 and a pipe 117 with a cylinder chamber 118 formed at the left hand end of the feed cylinder 45.

A pair of pull-type solenoids 53a and S311 are provided for shifting the valve member 96 toward the right or toward the left when energized. When the solenoid 83a is energized the valve member 96 moves toward the left so that fluid under pressure entering the valve chamber passes through the pipe 89 into the cylinder 85 to impart a compensating adjustment to compensate for undersize work. At the same time fluid under pressure from a valve chamber 100 passes through the pipe to move the feed piston 46 toward the right. During this movement fluid within the cylinder chamber 114 exhausts through the pipe 113, the valve 112, the pipe 111, through a pipe 116, through the valve chamber 98 and through a pipe 128 into the reservoir 107. The valve member 96 remains in a left hand end position momentarily after which the solenoid 53a is deenergized in a manner to be hereinafter described to allow the valve member 96 to return to a central position so that fluid under pressure within the pipe 108 passes through a pipe or passage 119, through the valve chamber 102, the pipe 111, the valve 112, the pipe 113 into the cylinder chamber 114 to return the feed piston 46 into a left hand end position. During this movement of the piston 46 toward the left, fluid within the cylinder chamber 118 exhausts through the pipe 117, the valve 116, the pipe 115, into the valve chamber 99, through the central passage 183 into the valve chamber 98 and exhausts through a pipe into the reservoir 107.

Similarly when the work piece is oversize, the solenoid 83b is energized to shift the valve member 96 toward the right so that fluid under pressure from the valve chamber 100 passes through the pipe 79 into the cylinder chamber:

on the feed wheel 35. At the same time fluid under pressure from the valve chamber 10!) passes through the pipe 115, through the valve 116, the pipe 117 into the cylinder chamber 118 to move the piston 46 toward the right (Fig. 3) to impart a winding motion to the feed screw 21 after which the piston 46 is moved toward the left to unwind the feed screw 21 after the compensating adjustment has been made to facilitate taking up the feed increment and also to take-up any backlash within the parts of the feed mechanism. The operation of the feed piston 46 by an in timed relation with the control valve 95 serves to obtain a winding and unwinding of the feed screw during a feed compensation, is particularly applicable to a centerless grinding machine of the straightthrough type.

In a plunge cut grinding operation, such as is employed either in a centerless grinding machine or a cylindrical grinding machine, the feed cylinder 45 is connected with the conventional feed control valve (not shown) such as is disclosed in the prior US. Patent No. 2,572,529 to H. A. Silven, dated October 23, 1951, to which reference may be had for details of disclosure not contained herein. In such an arrangement, the cylinder chamber 118 is connected by pipe 117 with a valve 121 and a pipe 122 which connects with the feed control valve. Similarly the valve chamber 114 is connected by the pipe 113 and a valve 123 and a pipe 124 with the feed control valve. When the machine is set up for a plungecut grinding operation, the valves 112 and 116 are closed thereby rendering the inner connection between control valve 95 and the feed cylinder 45 inoperative. The valves 121 and 123 are opened so that the normal feed control valve (not shown) controls movement of the piston 46. With the machine set up in this manner the normal feed movement of the piston 31 serves to wind and unwind the feed screw. When the machine is set up for a straight through centerless operation, the valves 121 and 123 are closed thereby cutting off the normal feed control valve (not shown) since no infeed is required. In this latter set up the valves 116 and 112 are open so that the control valve 95 not only actuates the feed piston 46 but also the oversize and undersize compensators above described.

A manually controlled work gauging mechanism is provided for actuating the pawl and ratchet compensating mechanisms above described to compensate for oversize or undersize work pieces. The mechanism is arranged so that after a predetermined number of work pieces have been gauged, if a plurality of work pieces are successively ground to an oversize, the piston 76 is actuated to reset the stop abutment 60 on the feed wheel 35 to grind the successive work pieces to a predetermined size. Similarly if a plurality of successively work pieces are gauged after grinding which are undersize, the piston 86 is actuated to impart a counter-clockwise adjustment to the stop abutment 60 relative to the feed wheel 35. A work gauge 125 is provided having a V-shaped support 126 for a ground work piece 15. A movable gauge member 127 is provided having an inverted V-shaped surface 128 which is arranged to engage'the upper surface of a work piece 15 when the gauging member 127 is moved downwardly. The gauging member 127 is provided with a slidably mounted plunger 129 for actuating a limit switch LS1. The limit switch LS1 is normally held in the position illustrated in Figure 3 by a compression spring 1311 which holds a pair of contacts 131 closed. A second pair of contacts 132 are normally open and are arranged to be closed when the plunger 129 is moved upwardly relative to the gauging member 127.

The gauging member 127 is supported by a rock arm 135 which is pivotally supported by a stud 136 on a vertically arranged bracket 137 extending upwardly from the gauge 125. The right hand end of the rock arm 135 is connected by a stud 138 with the gauging member 127. A hydraulically operated mechanism is provided for moving the gauging member 127 to and from an operative position comprising a cylinder 139 which contains a slidably mounted piston 140. The piston 140 is fixedly mounted on the lower end of a piston rod 141. The upper end of the piston rod 141 is con nected by a stud 142 with the left hand end of the rock arm 135. When fluid under pressure is passed through a pipe 143 into a cylinder chamber 144, the piston is moved downwardly into its lowermost position thereby rocking the rock arm 135 in a counterclockwise direction to raise the gauging member 127 to an inoperative position. During the downward movement of the piston 140, fluid within a cylinder chamber 145 exhausts through a pipe 146, through a needle valve 147 and through a pipe 148. A ball check valve 149 is provided to bypass fluid under pressure when passed through the pipe 148 into the pipe 146 to cause a rapid upward movement of the piston 145. A control valve 150 is provided for controlling the admission to and exhaust of fluid from the cylinder 139. The valve 150 is a piston type valve comprising a slidably mounted valve member 151 having a plurality of spaced valve pistons formed integrally therewith to form a plurality of spaced valve chambers 152, 153 and 154. The slidably mounted valve member 151 is provided with a central passage 155 which interconnects the valve chambers 152 and 154. A compression spring 156 serves normally to hold the valve member 151 in a left hand end position. A push-type solenoid S2 is provided which when energized serves to shift the slidably mounted valve member toward the right so as to reverse the flow of fluid under pressure between the valve 150 and the cylinder 139.

When the solenoid S2 is energized and the valve member 151 is shifted to a right hand end position fluid under pressure from the pipe 108 enters the valve chamber 153 and passes through the pipe 148, through both the ball check valve 149 and the needle valve 147 through the pipe 146 into the cylinder chamber 145 to cause an upward movement of the piston 140. The upward movement of the piston 1% serves to rock the rock arm 135 in a clockwise direction to move the gauging member 127 downwardly so that the V-shaped surface 128 engages the upper portion of the work piece 15. If the work piece has been ground to a predetermined size, an upward movement will be imparted to the plunger 129 relative to the gauge member 127 to open the normally closed contacts 131 and to maintain the contacts 132 open. If the ground work piece 15 is oversize, the normally closed contacts 131 will remain closed and the normally closed contacts 132 will remain open. If the work piece 15 has been ground undersize, an upward movement of the plunger 129 during the downward movement of the gauging member 127 will open the normally closed contacts 131 and close the normally open contacts 132 in a manner to be hereinafter described.

Describing Fig. 3, relay switch TD2 is a time delay relay which when energized momentarily closes the normally open contacts 160 which remain closed for a predetermined time interval after deenergization. Relay switch TD3 is a time delay relay Which when energized does not actuate the contacts thereof for a predetermined time interval after energization. The electric counter T3 at count-out serves to energize the solenoid 53a to shift the valve member 96 toward the left to pass fluid under pressure through the pipe 89 to cause an upward movement of the piston 86, to impart a compensation adjustment to the stop abutment 60 in a counterclockwise direction (Fig. 2) relative to the gear 39 and the stop surface 61 on the pawl 62 to compensate for undersize work. The electric counter TD4 at countout serves to energize the solenoid S312 to shift the valve member 96 toward the right to pass fluid under pressure through the pipe 79 to cause an upward movement of the piston 76 which, in turn, imparts a compensating adjustment to the stop abutment 60 in a clockwise direction (Fig. 2) relative to the gear 35 and the stop surface 61 on the pawl 62 to compensate for oversized work.

The operation of this work sizing and compensating mechanism will be readily apparent from the foregoing disclosure. The switch SW1 is closed to supply electric power to the operating circuits. The switch SW2 is then closed to start the pump driving motor to supply fluid under pressure to the fluid pressure system. The closing of the switch SW1 serves to energize the clutch coils TCH3 and T CH4 respectively of the electric counters T3 and T4 through the now closed contacts of relay switch TD3. When the clutch coils TCH3 and TCH4 are energized, the contacts CC3 of timer T3 and CC4 of timer T4 close to pass current to the contacts of the limit switch LS1.

When it is desired to gauge a ground work piece, the work piece is either placed manually or automatically onto the V-shaped surface 126 of the gauge 127 after which the push button switch PBS is momentarily closed. If desired, a switch SW3 may be provided which is actuated automatically by the work piece 15 when it is moved into an operative position onto the gauging surface 126. The momentary closing of either the switch PBS or the switch SW3 serves to energize the relay switch TD2 to close the contacts 160 thereof. The closing of the contacts 160 serves to energize the solenoid S2 to shift the valve member 151 toward the right so that fluid under pressure is passed through the pipe 146 to cause an upward movement of the piston 140 thereby moving the gauging member 127 downwardly into an operative gauging position. The closing of the contacts 160 of the relay switch TD2 serves also to energize the relay switch TD3. The contacts of TD3 remain in the position illustrated in Fig. 3 for a predetermined time interval after energization of TD3. These contactors remain in the position illustrated in Fig. 3 until the gauging member 127 has moved into an operative gauging position at which time the normally open contacts 161 and 164 close and the normally closed contacts 162, 163, 165 and 166 open.

If the ground work piece 15 is oversize, the contacts 131 of the limit switch LS1 remain closed when the gauging member is in a downward gauging position.

rough the normally closed contacts 131 of the limit switch LS1, a relay switch CRSb is energized and through the now closed contacts 164 of the relay switch TD3 imparts a counting impulse to the count coil ACH4. The energizing of the relay switch CR3b closes the contacts 167 to hold the clutch coil TCH4 of the counter T 4- energized during the counting interval. If the next work piece 15 to be gauged is either of correct size or undersize, the contacts 131 of the limit switch LS1 will open and the relay switch CRSb will not be energized and there is no holding circuit established for the clutch coil TCH4 and the counter T4 automatically reset.

The counters T3 and T4 may be set for operation after any predetermined number of impulses have been imparted to the count coils ACH3 and ACH4. If the counter T4is set for actuation after gauging four work pieces, the operation will be identical with the just described. If four consecutive ground work pieces are over size, the count coil ACH4 will be actuated four times at which time the timer T4 will count out closing the contacts LC4 so as to energize the solenoid 83b to shift the valve member 96 to the right thereby passing fluid under pressure through the pipe 79 to cause an upward movement of the piston 76 to impart a compensating adjustment to the stop abutment 60 in a clockwise direction to compensate for the oversize condition of the work so that future work pieces will be ground to a predetermined size.

When a work piece 15 is ground undersize, the downward movement of the gauging member 127 causes the plunger 129 to engage the surface of the ground work piece and actuates the limit switch LS1 to close the contacts 132. The closing of the contacts 132 serves to energize the relay switch CR3a and through the now closed contacts 161 of the relay switch TDSimparts an impulse to the count coil ACH3 of the timer T3. The energizing 8 of the switch CR3a closes the contacts 168 to set up a holding circuit to hold the clutch coil TCH3 of the timer T3 energized. Shortly after the energization of the counter coil ACH3 of the timer T3, the relay switch TD2 times out and the contacts 160 open thereby deenergizing the solenoid S2 to shift the valve 150 so as to raise the gauging member 127 to an inoperative position. At the same time the time relay TD3 is deenergized and the contacts return to the position shown in Fig. 3. If the counter T3 is set for actuation after gauging four work pieces, the above operation is repeated providing that four consecutive work pieces are ground undersize. After the fourth undersize workpiece has been gauged the counter T3 counts-out closing the contacts LC3 to energize the solenoid 83a which shifts the valve member 96 toward the left so that fluid under pressure within the valve chamber 100 passes through the pipe 89 to cause an upward movement of the piston 86 to impart a counter-clockwise compensation to the stop abutment 60. The solenoid S311 remains energized until the time relay TD2 times out. When the time delay relay TD2 times out the valve is shifted to raise the gauge member 127 to an inoperative position and also to deenergize the relay TD3. The timing out of relay TD2 serves to deenergize the relay T D3 operations to reset the counter T3. When the timer T3 resets, the contacts LC3 open to deenergize the solenoid 53a thereby allowing the valve member 96 to return to a central position.

If the ground work pieces are ground to a predetermined size, the contacts 131 and 132 of the limit switch LS1 both remain open when the gauge member 127 is moved downwardly into a gauging position and no counting impulse is imparted to either of the counters T3 or T4. If the count coils ACH3 or ACH4 of the counters T3 and T4, respectively, have been previously energized due to a work piece being oversize or undersize, the opening of both sets of contacts 131 and 132 of the limit switch LS1 during gauging a correctly size work piece serves to prevent setting up a holding circuit to the clutch coil T CH3 or TCH4 and the counter automatically resets.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinabove set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a grinding machine having a transversely movable wheel slide, a rotatable grinding wheel thereon, a feeding mechanism to feed said slide in either direction, a rotatable feed wheel to actuate said feeding mechanism, an adjustable stop abutment on said feed wheel, a stop pawl arranged in the path of movement of said abutment, and a compensating mechanism on said feed wheel including a pair of independent fluid pressure actuated pawl and ratchet mechanisms to adjust the position of said stop abutment in either direction so as to compensate for oversize or undersize work.

2. In a grinding machine having a transversely movable rotatable grinding wheel, a nut and screw mechanism to feed said wheel transversely in either direction, a gear mechanism to actuate said nut and screw mechanism, a rotatable feed wheel, an adjustable stop abutment on said feed wheel, a stop pawl arranged in the path of movement of said abutment, a pinion on said feed wheel which meshes with said gear mechanism, and a compensating mechanism on said feed wheel including a pair of independent pawl and ratchet mechanisms to impart a rotary motion to said pinion in opposite direction to adjust the 9 position of said stop abutment so as to compensate either for undersize or oversize work.

3. In a grinding machine, as claimed in claim 1, in combination with the parts and features therein specified in which the pawl and ratchet mechanism comprises a pawl and ratchet operatively connected to impart a clockwise adjustment to said stop abutment relative to the feed wheel to compensate for oversize work, and an independent pawl and ratchet mechanism operatively connected to impart a counter-clockwise adjustment to said stop abutment relative to the feed wheel to compensate for undersize work.

4. In a grinding machine, as claimed in claim 1, in combination with the parts and features therein specified of a work gauge, and operative connections between said gauge and said pawl and ratchet mechanisms to impart a compensating adjustment to one of said mechanisms after a predetermined number of consecutive work pieces have been ground either oversize or undersize.

In a grinding machine, as claimed in claim 1, in combination with the parts and features therein specified of a work gauge, an electric counter operatively connected therewith, and connections between said counter and said pawl and ratchet mechanisms to actuate one of said pawl and ratchet mechanisms after a predetermined number of consecutive work pieces have been ground either oversize or undersize to impart a compensating adjustment to said stop abutment.

6. Ina grinding machine, as claimed in claim 1, in combination with the parts and features therein specified in which the pawl and ratchet mechanism comprises a pawl and ratchet compensating mechanism operatively connected to impart a compensating adjustment to said stop abutment for oversize work, an independent pawl and ratchet compensating mechanism operatively connected to impart a compensating adjustment to said stop abutment in the opposite direction for undersize work, a work gauge, and an independent electric counter operatively conected between said gauge and each of said pawl and ratchet compensating mechanisms to impart a compensating adjustment to said stop abutment after a predetermined number of consecutive work pieces have been ground either oversize or undersize.

7. In a grinding machine, as claimed in claim 1, in combination with the parts and features therein specified in which the pawl and ratchet mechanism comprises a fluid pressure actuated pawl and ratchet mechanisms to impart a clockwise adjustment to said stop abutment relative to the feed wheel to compensate for oversize work, and an independent fluid pressure actuated pawl and ratchet mechanism operatively connected to impart a counter-clockwise adjustment to said stop abutment relative to the feed wheel to compensate for undersize work.

3. In a grinding machine, as claimed in claim 6, in combination with the parts and features therein specified of a control valve operatively connected to actuate each of said fluid operated pawl and ratchet mechanisms, an independent solenoid to shift said valve in either direction, and an independent switch operatively connected to actuate each of said solenoids to facilitate either an oversize or an undersize feed compensation.

9. In a grinding machine, as claimed in claim 6, in combination with the parts and features therein specified of a control valve operatively connected to actuate each of said pawl and ratchet mechanisms, an independent solenoid to shift said valve in either direction, an independent electric counter operatively connected at countout to actuate each of said solenoids, and a gauge operatively connected to actuate said counters to facilitate either an oversize or an undersize compensation after a predetermined number of work pieces have been ground either oversize or undersize.

10. In a grinding machine, as claimed in claim 1, in combination with the parts and features therein specified in which the compensating mechanism includes a pair of compensators on said feed wheel, one for oversize and the other for undersize compensation, each of said compensators having a fluid pressure operated pawl and ratchet, a worm and worm gear actuated thereby to impart a precise compensating adjustment to said stop abutment relative to said feed mechanism.

11. In a grinding machine, as claimed in claim '1, in combination with the parts and features therein specified in which the compensating mechanism includes an oversize compensator on said feed wheel including a fluid pressure operated pawl and ratchet operatively connected to adjust said stop abutment relative to the feed wheel in one direction, an undersize compensator on said feed wheel including an independent fluid pressure operated pawl and ratchet operatively connected to adjust said stop abutment relative to the feed wheel in the opposite direction, a control valve operatively connected to control the flow of fluid under pressure to either of said compensators, an electric counter operatively connected at count-out to actuate said oversize compensator, an electric counter operatively connected at count-out to actuate said undersize compensator, and a work gauge actuated switch operatively connected to actuate either of said counters to facilitate actuation of said compensators when a predetermined number of consecutive work pieces have been gauged oversize or undersize automatically to impart a compensating adjustment to said stop abutment.

12. In a grinding machine, as claimed in claim 2, in combination with the parts and features therein specified in which the compensating mechanism includes an oversize compensator on the feed wheel including a fluid pressure actuated pawl and ratchet operatively connected to adjust said stop abutment relative to the feed wheel in one direction, an undersize compensator on said feed wheel including a fluid pressure actuated pawl and ratchet operatively connected to adjust said stop abutment relative to the feed wheel in the opposite direction, means including a piston and cylinder to actuate said nut and screw feed mechanism, a control valve operatively connected to control the flow of fluid under pressure to either of said compensators and simultaneously to said feed cylinder so as to impart a rotary motion in one direction to said nut and screw feed mechanism so as to unwind said nut and screw feed mechanism, to thereafter impart either an oversize or an undersize compensation to said stop abutment and thereafter to impart a rotary motion in the opposite direction to' said nut and screw feed mechanism so as to wind said nut and screw feed mechanism to position the operative face of the grinding wheel for succeeding grinding operations.

References Cited in the file of this patent UNITED STATES PATENTS Bindszus Oct. 30, 1955 

